But, “This is interesting,” he said, pointing to a note she had made about the application of a new kind of metal to steles. It turned out that what he found helpful was not intricate knowledge, but the willingness to sit with an idea, to turn it over in her mind and examine it from all angles. At some point she realized that it was not only Christopher’s curiosity and imagination that made him a scientist: it was patience. The patience to keep pressing against a problem until it yielded, rather than giving in to the frustrations of failure.

And then, as Christopher was jotting down a summary of their most recent idea, a knock came at the barred door, and suddenly Brother Zachariah was there, his parchment robes flowing silently around him.

And he was speaking in both their heads, and the words were a jumble of nightmare images. The Christmas party, invaded. Grace’s mother, bearing a sharp silver dagger, the blade to the throat of a little boy. The little boy who was Christopher’s brother. Tatiana vanishing, taking Alexander with her, the whole of the Enclave in pursuit.

There was a crash as Christopher shot to his feet, sending his glass of champagne flying. Without stopping to gather up his notes, or even to look at Grace, he bolted from the room. Zachariah regarded Grace for a moment in silence, then followed Christopher, closing the door behind him.

Grace sat on the bed, her blood turning to ice. Mother, she thought. I had made a friend. I had…

But that was just it, wasn’t it? Her mother would never allow Grace to feel anything, to think anything, to have anything that wasn’t about her. Grace was sure Tatiana had no idea that she’d ever spoken to Christopher Lightwood—but even so, Tatiana had made certain that she never would again.

“I’m not sure I can agree with that,” Alastair replied. They were sitting in the drawing room at the Institute. Alastair was industriously applying a second iratze to Cordelia’s hand, though the first one had already caused Cordelia’s cuts to scab over. He did not seem to have minded Cordelia getting blood all over his new jacket, and he held Cordelia’s hand with gentle care. “Being attacked by Mantids, which are quite revolting up close, and barely getting there in time to stop Tatiana from putting a rune on the child that would have killed him—” He finished her iratze and held out Cordelia’s hand to examine his work. “It wasn’t easy.”

“I know.” Cordelia looked around the room—everyone was milling about, talking in low voices: Will and Tessa, Lucie and Jesse and Thomas, Matthew and James. Only Ari sat by herself in an armchair, looking down at her hands. Anna had run back to the Institute with Alexander, not waiting for Tatiana to be dealt with, and was in the infirmary with him and her parents. He was being looked after by Brother Shadrach, who had said that while the injury might heal slowly, the rune had not been completed: no lasting harm had been done.

Cordelia knew Will would have preferred to have Jem looking after his nephew, but James had summoned Jem to arrest Tatiana at the house on Bedford Square and escort her to the Silent City, and Jem was busy with that. Meanwhile, Bridget had put out rather mad sandwiches (mince pie and pickle, sugar icing and mustard) and a great deal of very hot, very sweet tea, which she seemed to feel was the cure for shock, but nobody was eating or drinking much.

“But how did she get out? I don’t understand what happened,” Thomas was saying. “Tatiana was found barely alive on Bodmin Moor. She was awaiting transport at the Cornwall Institute. In the Sanctuary. How did she get to London so quickly, and without any sign of being hurt?”

“It wasn’t Tatiana,” Tessa said. “I mean, in Cornwall. It was never her.”

Will nodded wearily. “We heard from the Silent Brothers—too late, alas. It was all a trick.” He drew a hand across his eyes. “The thing Pangborn found on the moors was an Eidolon demon. Brother Silas was sent to retrieve Tatiana, but when he arrived at the Cornwall Institute, all he found was a bloodbath. The demon slaughtered everyone in the place before it fled. A reward for its service to Belial, no doubt. It did not spare even the mundane servants. The body of a young girl was found on the front steps, horribly mutilated—she had crawled there, no doubt trying to summon help.” His voice shook. “Awful stuff, and all simply to fool us into believing Tatiana was not at large.”

Silently Tessa took Will’s hand and held it in her own. Will Herondale was like his son, Cordelia thought; both felt things strongly, however they might try to hide it. When they had all returned to the Institute, bloody and scratched but with the news that Tatiana had surrendered, Will had rushed over to make sure Lucie and James were all right. Once he had reassured himself, he looked down at James and said in a flat, humorless voice, “You did good work, James, but you broke a promise to do it. This night’s events may have worked out, but they very easily could have gone terribly wrong. You might have been hurt, or your sister, or you might bear the responsibility for someone else’s death or wounding. Don’t do something like this again.”

“Forgive me,” James had said, standing very straight, and Cordelia recalled him saying to her, I’ll have to beg his forgiveness later. He could have protested, she had thought; he could have told Will that they could not in good conscience have failed to act on Jesse’s convictions. But he said nothing. He was proud and stubborn, Cordelia thought, just as she herself was. And she thought of Lucie.

You—you’re soproud, Cordelia.

It had not been a compliment.

Will had only touched James on the cheek, still frowning, and led them all upstairs to the drawing room. Cordelia glanced over at Lucie now, but she was in quiet conversation with Jesse and Thomas.

“But what about the wards?” Ari asked. “At the Cornwall Institute. I understand that they let the demon into the Sanctuary, but shouldn’t the wards have prevented it, or sent up some kind of warning?”

“It seems Pangborn had let the wards around his Institute lapse.” Will shook his head. “We all knew he was old, probably too old to have the job he did. We should have done something.”

“It was a clever trick,” said Matthew, who was leaning back in an armchair. He had used all his chalikars in the Mantid battle, and there were bruises on his neck and collarbones. “But if it had not been Pangborn’s weakness, Belial would have found some other way to play it.”

“It meant we let our guard down,” said Tessa. “At least where Tatiana was concerned. The Institute is well warded against demons, but not against Shadowhunters.”

“Even really evil Shadowhunters,” added Lucie fiercely. “They should have stripped her Marks at the Adamant Citadel.”

“I’m sure they will now,” said James, “since the Mortal Sword will drag the truth out of her and reveal all her past crimes. Perhaps we’ll finally discover something useful about Belial’s plans as well. I am sure they do not end here.”

“Speaking of Belial,” Will said in a heavy voice, “the Inquisitor has called a meeting for tomorrow. To discuss the issue of our family.”

“I do not see how our family is any of his business,” James began hotly, but to Cordelia’s surprise, Lucie cut in.

“He is going to make it his business, James,” she said. “The Institute may be the only home we’ve ever known, but it doesn’t belong to us. It belongs to the Clave. Everything we have and everything we are is subject to the Clave’s approval. Think how many of the Enclave have always been awful to Mother just because she was a warlock—because she has a demon parent. Before they ever knew he was a Prince of Hell to boot.” Her voice was tight, lacking any of Lucie’s usual optimism; it hurt to hear. “We should have known that they would turn on us the moment they found out about Belial.”

“Oh, Lucie, no.” Cordelia bolted to her feet before she could stop herself. Lucie looked at her in surprise. In fact, Cordelia could feel every eye in the room on her. “The Inquisitor can fuss and fume all he wants,” she said, “but the truth is on your side. The truth matters. And the Enclave will see it.”

Lucie looked at Cordelia calmly. “Thank you,” she said.

Cordelia’s heart sank. It was the sort of thank you that you’d offer to someone you didn’t know very well after they’d apologized for stepping on your foot at a party. But before she could reply—or even sit down in embarrassment; everyone seemed to be staring at them—the drawing room door flew open, and Christopher came in.

He looked as if he had run halfway across London. He was coatless, his boots and trousers splashed with icy mud, his bare hands red from the cold. His eyes, behind his glasses, were wide and stunned. Cordelia was reminded for a moment of someone else—and then realized it was Alexander, as Tatiana tormented him, his eyes full of a terrible confusion that anyone could wish to cause him pain.

“What happened?” he said, in a half whisper, and then Thomas, James, and Matthew were surging over to him, hugging him tightly, their voices overlapping as they explained that Alexander was fine, that Tatiana had been caught, that his little brother was being taken care of in the infirmary. That he would be all right.

“I just don’t understand,” Christopher said, the color coming back slowly to his face. He was clinging to Matthew’s sleeve with one hand, his shoulder touching James’s. “Why Alexander? Who would want to hurt a baby?”

“Tatiana wants to hurt us, Kit,” Tessa said. “She knows the best way to do it is through our families. It’s the worst pain she can think of to inflict. Any of us would gladly suffer in place of our children, but to have them suffer in our place is… horrifying.”

“She has been brought to the prisons of the Bone City,” said Will. His voice was cold. “So we will have ample opportunity to ask her.”

Christopher’s eyes widened. “They’re holding her in the Silent City?” he said, sounding inexplicably unhappy with this development.

Jesse appeared disturbed as well. As if he had suddenly realized something, he said sharply, “They keep the prisoners apart from each other, right? They must. She must not get near Grace.”

“They would never let that happen,” Will began, and then Cecily appeared at the door and flew to hug Christopher. “Come upstairs, darling,” she said. “Alexander is sleeping, but he might wake at any time, and he will want to see you.” She turned to Ari with a warm smile. “And Anna asks that you come as well, my dear. We would love to have you with us.”

Ari’s face lit up. She rose to her feet and joined Christopher and Cecily as they left the room. Jesse watched them go, a grim look on his face. Thinking about Grace? Cordelia wondered. Or more likely, about Tatiana, and what would happen now.

“All my life my mother has told me how much she hates you, all of you,” Jesse said. He was leaning against the wall, as if he required it to hold him up. “Now that she knows I have joined with you, fought beside you against her—she will see it as a betrayal even more profound.”

“Does it matter?” said Matthew. “She is mad; if she does not have a reason to be full of hate, she will invent one.”

“I am only thinking,” Jesse said, “she knows who I am, that I am among you. Nothing will stop her from telling the Clave once she is questioned. Perhaps I could help you, if I told the Enclave first. If I confessed who I truly am—Jesse Blackthorn—I could testify to my mother’s madness and lying, her hate for you, her need for revenge.”

“No,” James said, very gently. “That is a generous offer, considering what it would mean for you, but it would only further darken the Enclave’s view of us, if they believed Lucie had engaged in necromancy.” He held up a hand as Lucie began to protest. “I know, I know. It wasn’t necromancy. But they will not see it that way. And there is every chance Tatiana will not immediately spill the truth about you, Jesse; it reveals too many inconvenient facts about her own crimes. About her relationship with Belial.”

“Speaking of Belial,” Will said. “It is kind of you to try to spare us, Jesse, but it is past time for us to face all this, rather than leaving it hanging like a sword over our heads. We have kept this secret too long—forgetting, I think, that secrets give others power over you.”

Tessa nodded. “I wish we’d simply told everyone the moment we learned. Now we have to separate the truth from the fiction that we are in league with Belial.” She snorted, which made Cordelia smile; it was a very unladylike gesture for Tessa. “?‘In league.’ The notion is medieval and thoughtless. Is Magnus ‘in league’ with his demon parent? Is Ragnor Fell? Is Malcolm Fade? No, no, obviously no: that’s been settled business for hundreds of years.”

“At least it’s only your word against Tatiana’s,” Cordelia said, “and I think most people know her word isn’t worth very much.”

“What will happen at the meeting tomorrow, do you think?” Alastair said.

Will spread his hands. “It’s hard to say. This is exactly the kind of thing the Mortal Sword is for, and of course Tessa and I would hurry to Idris at any moment to testify to the truth. But it would be extreme even of Bridgestock to push the issue that far. I suppose it depends how much annoyance Bridgestock feels like causing us.”

Matthew groaned. “He loves causing annoyance.”

“Good gracious,” said Tessa, glancing at the clock over the mantel. “It’s one in the morning. We must all get some rest before tomorrow, which promises to be rather unpleasant.” She sighed. “Cordelia, Alastair, I shall walk you downstairs to your carriage.”

Alastair and Cordelia exchanged a glance. This was an odd offer. They could manage to find their way to the front door themselves, of course; or Will or James would be the usual ones to offer. Tessa, however, seemed firm in her resolve.

Alastair went to say something quick and quiet to Thomas. Wanting to give him a moment, Cordelia took her time putting away her ruined gloves and tying her scarf around her neck. As she dusted herself off, she felt a gentle touch on her shoulder.

It was James. The cut over his eye had mostly healed, though she thought he might have a scar through his eyebrow. It would look rather dashing, of course; that always seemed to be the way of things. “You’re right,” he said, in a low voice.

“Probably,” Cordelia said. “But—about what, exactly?”

“It was too easy,” James said. “Tatiana wanted to be caught. She snatched Alexander, ran a little distance away, and waited to be arrested. I could not for the life of me say why, however.” He hesitated. “Daisy,” he said. “The thing you said you had to do, earlier—did you do it?”

She hesitated. It felt a thousand years since she had stood in the games room with Matthew, a thousand lifetimes ago that they were all at a party together. It seemed as though she had been a different person entirely then, though only a few hours had passed.

“I did,” she said. “It was awful.”

James looked as if he very much wanted to ask something else. But then Tessa came up to them, and with her usual deftness had in moments drawn Cordelia away and was leading her, along with Alastair, downstairs.

The cold air outside was a shock after the warmth of the drawing room. The carriage was brought round quickly, and Alastair clambered in. He seemed to sense that Tessa wanted a moment to speak to his sister alone, and perhaps sensed as well that it might be awkward. He drew the curtains of the carriage closed, giving Cordelia and Tessa as much privacy as could be managed.

“Cordelia,” Tessa said gently, “there is something I had to say to you.”

Cordelia took a deep breath of icy air. She felt the loneliness she associated only with London: of being both one of millions together in the dark of the city, and of being utterly alone in that same dark.

Tessa said, “I know it is reasonable that you should be with your mother now. But I am not entirely oblivious. I know it is not only that. Things are not well between you and James. Or between you and Matthew, for that matter.”

“Or between James and Matthew,” Cordelia said. “I am so sorry. You trusted in me to make James happy, and I am doing exactly the opposite.”

After a moment Tessa said, “I know people hurt one another. I know relationships are complicated. Believe me. But it’s been my experience that—well, that when everyone loves one another enough, there will always be a way for things to come out all right in the end.”

“That’s a lovely thought,” Cordelia said. “I hope you’re right.”

Tessa smiled. “I have been so far.”

And with that, she ducked back into the Institute. Cordelia was just reaching for the handle of the carriage when she heard the sound of running feet behind her. Perhaps Tessa had forgotten to tell her something else, or Thomas—

But it was Lucie. Lucie, in her gear jacket and lavender dress, the ruffles on the hem flying around her like sea-foam. She hurtled down the steps and flung herself into Cordelia’s arms, and Cordelia could feel that she was shaking as if with a terrible chill.

Cordelia’s whole heart melted. She tightened her arms around Lucie, rocking her a little, as if she were a child.

“Thank you,” Lucie whispered, her face buried in Cordelia’s shoulder. “For what you said.”

“It was nothing,” Cordelia said. “I mean, it was true. It was a true nothing.”

Lucie sniffled an almost-laugh. “Daisy,” she said. “I’m so sorry. And I’m so awfully scared.” Her breath hitched. “Not for me. For my family. For Jesse.”

Cordelia kissed the top of Lucie’s head. “I won’t ever leave you,” she said. “I will always be right beside you.”

“But you said—”

“It doesn’t matter what I said,” Cordelia said firmly. “I will be there.”

The door of the carriage cracked open, and Alastair glared out peevishly. “Really,” he said. “How many meetings are you planning to have on these steps, Layla? Should I be preparing to spend the night in this carriage?”

“I think that would be very gracious of you,” said Cordelia, and though it wasn’t terribly funny, she and Lucie both laughed, and Alastair grumbled, and for just those few moments, everything felt as if it were going to be all right.